A SERS aptasensor based on AuNPs functionalized PDMS film for selective and sensitive detection of Staphylococcus aureus

In this study, a sensitive biosensor was developed based on aptamer functionalized polydimethylsiloxane (PDMS) film for the detection of Staphylococcus aureus (S. aureus) using surface-enhanced Raman scattering (SERS) technology. Initially, the surface of PDMS film was chemically modified by piranha solution and 3-Aminopropyltriethoxysilane (APTES), and then AuNPs-PDMS film was prepared by coating gold nanoparticles (AuNPs) through electrostatic interaction. Next, the aptamers were immobilized on the AuNPs-PDMS membrane via gold sulfur bond to form the capture substrate. Meanwhile, gold-silver core-shell nanoflowers (Au@Ag NFs) modified with mercaptobenzoic acid (4-MBA) and aptamers were applied as a signal probe. In the presence of the target, the signal molecular probe and the capturing substrate specifically combined with the target and resulted in a sandwich structure capture substrate-target-signal molecular probe. Under the optimized experimental condition, the signal of 4-MBA at 1085 cm(-1) was linearly related to the S. aureus concentration in the range of 4.3 x 10 cfu mL(-1) 4.3 x 10(7) cfu mL(-1) (y = 326.91 x 117.62, R-2 = 0.9932) with a detection limit of 13 cfu mL(-1). The method was successfully applied to spiked actual samples and a 92.5-110% recovery rate was achieved.

Automated summary

A sensitive biosensor based on aptamer-modified PDMS film was developed for the detection of Staphylococcus aureus using SERS technology, showing a linear relationship between the signal of mercaptobenzoic acid at 1085 cm(-1) and S. aureus concentration.